Apparatus for producing small castings



June 2, "1942. w. D. MOORE 2,284,835

APPARATUS FOR PRODUCING SMALL CASTINGS Filed Jan. 22, 1940 s Sheets-Sheet 1 E E '5 g E 4 8 INVENTOR.

g E m ATTORNEYS June 2, 1942. w. D. MOORE APPARATUS FOR PRODUCING SMALL CASTINGS 3 Sheets-Sheet 2 Filed Jan. 22, 1940 INVENTOR. 097% \ATTORNEYS June 2, 1942. I w, oo 2,284,835

I APPARATUS FOR PRODUCING SMALL CASTINGS Filed Jan. 22, 1940 s sheets-sheet s INVEN OR. BY QM.

. ATTORNEYS Patented June 2, 1942 APPARATUS FOR PRODUCING SMALL CASTIN GS William D. Moore, Birmingham, Ala., assignor to American Cast Iron Pipe Company, Birmingham, Ala., a corporation of Georgia Application January 22, 1940, Serial No. 315,088

1' Claim.

This invention relates to the manufacture of iron castings by automatic or semiautomatic machinery, and more particularly is concerned with a method and apparatus for the rapid pro-- duction of small castings. The invention is of particular utility in the production of cast iron bolts or the like, and will be exemplified by reference thereto, but as will be apparent to those skilled in the art the invention is of wider utility.

It is an objectof this invention to provide an improved method and apparatus for the rapid production of small castings which are possessed of improved characteristics. For example, the desirability of employing cast iron bolts of high strength in bolted cast iron pipe joints has long been recognized, because cast iron when buried in ordinary soils is known to have a relatively long life. However, in order to make cast iron bolts available economically, they must be produced at a low cost, which means on a quantity production basis wherein "equipment and labor costs are relatively low. 'F'urthermore in order that such bolts after proper heat treatment shall be readily machinable, and sufficiently strong without excessive brittleness; the bolts should be formed under such conditions that, a proper composition of iron being employed, nearly all of its contained carbon exists in the combined form in the casting'as cast.

It is an object of this invention to provide a method and apparatus of the type characterized which accomplishes the foregoing purposes.

Another object of this invention is to provide a method and apparatus of the type 'characterized which are simple in character, which do not require highly skilled labor, and which produce at a relatively highrate and low cost iron castings'which are possessed of or upon treatment can be made to have the desired characteristics of machinability, strength, toughness, elasticity, etc.

Other objects will appear as the description of the invention proceeds. v

The invention is capable of receiving a variety of mechanical expressions some of which are illustrated on the accompanying drawings,'but it is to be expressly understood that the drawings are for purposes of illustration only, and

are not to be construed as a definition of the limits of the invention, referencebeing had to the appended claim for that purpose.

Referring in detail to the accompanying drawings, wherein the same reference characters are employed to designate corresponding part in the several figures,

Fig. 1 is a somewhat schematic plan view of a casting machine for making bolts in accordance with the present invention;

Fig. 2 is a vertical axial cross-section of th embodiment of Fig. 1; g I

Fig. 3 is a plan view, on a larger scale, of one of the molds and its associated parts;

Fig. 4 is a vertical section through the parts shown in Fig. 3; and 1 Figs. 5 and 6 are sideand end elevations of a bolt blank as cast in the machine of Figs. 1 to 4.

In accordance with the present invention the castings are formed in a plurality of traveling molds whose movements and function are controlled automatically or semiautomatically so as to reduce to a minimum the need for personal supervision and control. In order that the castings shall be possessed of the desired characteristics after the cast blanks have been subjected to proper heat treatment the iron used contains a relatively high percentage of silicon, preferably from 2.50 to 4.00%, with carbon from 2.00 to 2.60%, and each mold is made of a material which has a much higher heat conductivity than green sand molds so as to effect a rapid cooling of the casting, to the end that nearly all of the carbon in the casting as cast shall be in combined form and show a white fracture. Furthermore, the use of iron of the composition referred to effects additional economies and therefore de:

crease in the cost of production both in the preparation of the iron to be castand in the subsequent treatment of the castings so formed, while at the same time the castings have the desired characteristics and properties as to machinability, toughness, strength, elasticity, etc., after such treatment.

In order to effect the aforesaid rapid cooling of the metal as cast, the preferred mold material is cast iron, because of its strength as Well as its good heat conductivity, but other known mold materials as graphite, silicon carbide, steel, etc., which are possessed of the requisite strength and heat conductivity, are also available and within the contemplation of the present invention. Whether the mold is made of cast iron, as at present preferred, or of ther materials as referred to, it may be provided with a permanent or semipermanent facing, and/or it may be coated before each casting operation as by spraying or the like with a suitable protective material as understood in the art.

By employing a mold of high heat conductivity, an iron high in graphitizing elements, such as silicon and carbon, may be used with the assurance that as cast nearly all of the carbon will be in the combined form and the iron as cast will have the desired white fracture. The higher content of silicon and/or carbon, which may thus be used because of the higher rate of cooling employed, renders the metal of lower freezing point, so that it may be prepared for casting at a lower temperature, and therefore with less expensive equipment, as in a cupola, for example; also the desired annealing treatment of the castings may be carried out with less expenditure of time, so that material economies are again effected in preparing the castings for use. Hence by using molds that chill the castings rapidly an iron composition may be used that is productive of economies and decreased cost at all stages of the manufacture thereof. The rapid cooling also results in smaller crystals, while the higher content of carbon and/or silicon also gives to the metal improved characteristics and properties that are of particular importance with regard to the uses to which it i put.

The composition of the metal used (in the case of bolts or the like preferably 2.00 to 2.60% carbon, 2.50 to 4.00% silicon, 0.60 to 1.00% manganese, less than 0.13% sulphur, less than 0.10% phosphorus and 0.75 to 1.25% copper) and the treatment to which it is subjected after casting (in the case of bolts or the like the preferred heat treatment including heating to a temperature of v at least 1750 F., preferably 1800 F., and maintaining that temperature for at least thirty minutes, preferably approximately one hour, then air cooling to a temperature on the order of about 1200 F., then reheating to a temperature of at least 1400 F., preferably 1450 F., and maintaining that temperature for at least thirty minutes,preferably three quarters of an hour, and then suitably cooling to atmospheric temperature), in order to provide the desired characteristics, are of wider utility than in the production of small castings with which the present application is concerned, and therefore are not disclosed in detail or claimed herein, being the subject matter of a separate application filed by me concurrently herewith, Serial No. 315,089, filed January 22, 1940, and entitled Composition and procedure for preparing cast iron products; the present invention is thus concerned with a method and an apparatus for making small castings which will be exemplified by bolts or the like to take advantage of the foregoing economics and advantages arising from the rapid cooling of the castings in the economical production of such castings.

In conformity with the present invention permanent molds that will effect a rapid cooling of the castings as before referred to are mounted in any suitable way so as to be brought in sequence through stations for casting the metal and then releasing the castings. The conveyor for the molds may take a wide variety of forms, and may move the molds into and out of their respective positions by traverse through a horizontally disposed path or a vertically disposed path or an inclined path. Associated with the molds and their conveyor is suitable mechanism, as hereinafter explained more in detail, whereby the molds are automatically or semi-automatically operated to release the castings, thereby reducing the need for attendants.

- Referring first to the embodiment of this invention shown in Figs. 1 to 4, inclusive, the molds which may be of any suitable number are mounted on a conveyor in the form of a horizontally disposed table l2 rotatably mounted on a foundation II which, as illustrated, takes the form of a concrete pit. Table I2 is rotatably supported in any suitable way, as by means of a bearing block diagrammatically illustrated at IS, the arrangement being such that the table is disposed at a convenient height above the floor [4 of the foundry for purposes that will be apparent.

Table I2 may be driven in any suitable way. As illustrated, the periphery of the table is grooved or channeled and with it cooperates a rope, chain or cable I5 which also passes around the grooved periphery of a pulley 16 on a vertical shaft ll. Shaft I 1 may be driven in any suitable way, as through suitable speed reducing mechanism l8 that is in turn driven from any suitable source of power, as a variable speed electric motor I9, with or without additional speed reduction means such as diagrammatically illustrated at 20. As here shown, the motor l9, together with the speed reducing mechanism I8 and 20, are all mounted on a base member 2| which is in turn supported on horizontal rollers 22 disposed lengthwise of a channel-shaped support 23 formed as a part of or suitably mounted on the foundation ll. Pivotally mounted at 24 on a stationary support 25, here shown as attached to the member 23, is a bell crank lever 26 carrying a counterweight 21, and a link 28 pivotally connects said bell crank lever 26 to base member 2| so that the counterweight 2'! exerts a constant pull on said member 2 I, tending to move it on its rollers 22 toward the right, as viewed in Fig, 2, whereby pulley l6 maintains the cable l5 under a substantially uniform condition of tautness.

By the mechanism so far described, the table I2 is continuously driven at a low rate of speed so as to bring the molds hereinafter referred to successively into position for receiving the metal to be cast. While as illustrated the table I2 is thus moved continuously at the desired rate of speed to bring the molds successively into casting position, it is to be expressly understood that if preferred suitable means may be interposed in the drive between the motor I9 and the turntable I 2 or the motor itself may be so actuated that the feed of the table is intermittent.

Table I2 is provided with any suitable number of molds, generally designated by the reference numeral 30. Only a few of the molds are illustrated in Fig. 1, the position of the others being indicated by dot and dash lines. Said molds may be of any suitable construction to carry into effect the purposes of the present invention, one suitable form of mold being illustrated in Figs. 3 and 4 when a cast iron bolt blank is to be formed. As here shown, each mold comprises two complemental cast iron half molds 30a, having complemental mold cavities 30b and gate halves 300 leading to the top of said mold cavities. Dowel pins 3003 in one mold half which engage in matched closely fitting apertures in the other mold half assure that when abutted the mold cavities are in register. The mold halves are separable and mounted in any suitable way so that one or both of the halves may be moved apart to discharge the casting. As shown, the inner half mold is stationary, being secured by cap screws 3| to the upper end of an upright arm 32 provided with a longitudinal slot 33 through which the cap screws are passed and relative position shown in Figs. 3 and 4.

by means of which vertical adjustment of the mold half with respect to its arm 32 is provided. Arm 32 as shown is part of a block 34 secured in any suitable way, as by bolts 35, to the top of the table 2 adjacent its periphery. The movable mold half is likewise secured by cap screws 36 to the slotted upper end of an arm 31 whereby its vertical position may also be adjusted as in the case of the stationary mold half. Arm 31 is secured in any suitable way to a horizontal rod 38 mounted to slide inbearings 39 and 40 provided in the block 34. Set screws 4| which pass through the arm 31 and engage the movable mold half are also preferably provided to enable precise lateral adjustment of said mold hall, and keys 42 or the like are also preferably disposed in suitable slots in the arms 32 and 31 to support the mold halves at the bottoms thereof.

Rod 38 is surrounded by a compression spring 43 whichreacts between a stationary part of the block 34, as the lower extremity of the arm 32, and a spring follower 44, here shown as pinned to the rod 38 and provided with an arm 45 whose upper bifurcated end 46 embraces a guide rod 41 suitably mounted on said block 34 and extending between the arm 32 and an arm 48 at the opposite extremity of the block 34. Spring 43 tends to hold the movable mold half abutted against the stationary mold half as shown, while the cooperation of the arm 45 with guide rod 41 assures against rotational displacement of the movable mold half with respect to the stationary mold half. Hence the two mold halves when abutted as shown are properly aligned so as to register the mold cavities therein, and precise registry is secured by reason of thedowel pins described. Instead of the illustrated arrangement, however, rotation of the rod 38 and its movable mold half may be prevented in any other suitable way, as for example by making the rod 38 of noncircular cross-section. A removable cover 49 is preferably mounted on the arms 32 and 48 so as to enclose the spring 43, the slidable rod 38 and its bearings and the guiding means 46, 41 against injury from molten metal being spilled thereonto.

In casting position the mold halves are in the For withdrawal of the casting from the mold, the

mold halves may be separated in any suitable way. As shown, a stationary horizontal cam 50 is suitably disposed above the table l2 with its periphery in alignment with rollers 5| mounted on the inner ends of the rods 38. Cam 58 is of such size and shape that the respective rollers 5| do not touch the cam when the mold halves are abutted and the molds are at and adjacent to the pouring station, but when the table l2 has moved a given mold around to that point where the casting is to be discharged, at the left in Fig. 1 where the releasing station is indicated, and therefore the mold halves are to be separated, cam 58 engages the respective cam roller 5| and moves its rod 38 against the compression of its spring 43 to separate the movable mold half from the stationary mold half a sufficient distance to permit the casting to be removed from the mold in any suitable way. The castings may be delivered into a chute (not shown) or other suitable conveyor for removing the formed castings from the machine and,'if desired, delivering them to any suitable remote location, as an annealing furnace. V

As illustrated, cam 50 is formed of angle iron bent to the shape shown in Fig. 1 and secured lustrated said member is braced by a channel member at its center and by V-shaped channel members 56 and 51 which abut said member 55. Channel member 51 also constitutes the support for the member 52, and to this end its extremities are bent upwardly and secured to suitable columns, here shown as in the form of H bars 58, whose lower ends are rigidly embedded in the foundation or otherwise suitably supported. It is to be understood, however, that any other suitable means for centering the table and for supporting the cam and its associated elements may be employed if preferred.

Cooperating with the mechanism as so far described is suitable ladle mechanism for pouring the molten metal in suitable quantity into each mold as it arrives at what has been indicated in Fig. l as the ,pouring station. As the molds are made of cast iron or other good heat-conducting material as before pointed out, the cast metal cools in the molds very rapidly. After a predetermined lapse of time each mold is then opened to permit the casting to be discharged therefrom. Where this will be in the traverse of the mold by reason of rotation of the table will of course depend upon the size of the table and the speed of its rotation as well as cooling time preferred. In the embodiment illustrated the casting release position is approximately 90 removed from the pouring station, but this position may be varied, depending upon the speed of movement of the mold, so that a predetermined lapse of time will occur after the metal is cast before the casting is discharged from the mold. When the mold halves are opened by the cam 50 the casting may be manually removed, dropped or ejected from the mold as hereinbefore or hereinafter referred to, and the mold halves are thereafter retained in their relatively open position until they are again approaching the pouring station so as to facilitate cooling of the mold halves and also to permit an operator to paint, spray, or otherwise coat the faces of the mold cavities with any suitable material as heretofore referred to, if such is desired.

It will be noted that the blank as cast has no gate, and takes the general form indicated at 60 in Figs. 5 and 6. These blanks are subsequently annealed as explained in the companion applicaused may be such as to effect important economies both in the preparation of the metal for casting and in the subsequent treatment of the castings. At the same time the method and apparatus are such that the castings may be formed at relatively high speed and produced in quantity by a procedure that requires a minimum number of attendants. Hence the method and apparatus 'of the present invention provide for the production of small castings, as cast iron bolts for example, at a relatively low cost while at the same time they are possessed of superior characteristics as heretofore pointed out.

While the embodiments of the invention illustrated on the drawings have been described with considerable particularity, it is to be expressly understood that the invention is not restricted thereto, as other embodiments of the invention will now readily suggest themselves to those skilled in the art, while changes may be made in the details of construction, arrangement, size, and proportion of parts, and certain features may be used without other features, Without departing from the spirit of this invention. Reference is therefore to be had to the appended claim for a definition of the invention.

What is claimed is:

Apparatus for producing small iron castings including a horizontally disposed table, means supporting said table for rotation around a vertical axis, means for rotating said table around said axis, a plurality of mold units mounted on said table adjacent the periphery thereof, each of said mold units including a permanent mold of good heat conductivity composed of two relatively movable mold parts, resilient means normally urging said mold parts together, a frame in which one of said mold parts is fixedly mounted, a rectilinearly-movable radially-disposed rod mounted for reciprocation in said frame and having its outer end operatively connected to the other of said mold parts, means mounted on each rod and cooperating with a stationary member for preventing relative rotation of the rod and its associated mold part, cooperating means on said relatively movable mold halves for maintaining exact registry therebetween during their relative movement into and out of cooperative relationship, and a stationary cam disposed above and substantially coaxial with said table and adapted to cooperate with the inner ends of said rods to reciprocate said rods in said frames and move the mold halves relatively to each other to release the castings from said molds.

WILLIAM D. MOORE. 

